Ozone and tracer transport variations in the summer Northern Hemisphere stratosphere

Constituent observations from the Upper Atmosphere Research Satellite (UARS ) in combination with estimates of the residual circulation are used to exa mine the transport and chemical. budgets of HF, CH4 and O-3 in the summer N orthern Hemisphere. Budget calculations of HF, CH4 and O-3 show that the tr ansport tendency due to the residual circulation increases in magnitude and is largely opposed by eddy motions through the summer months. Ozone budget analyses show that between 100 and 31 hPa, the magnitudes of the mean circ ulation and eddy transport terms increase through the summer months, produc ing tendencies that are factors of 2 to 3 times larger than the observed oz one change in the stratosphere. Chemical loss dominates the observed ozone decrease only at the highest latitudes, poleward of about 70 degreesN. A co mparison of observations from the Total Ozone Mapping Spectrometer with UAR S-calculated total ozone suggests that poleward of 50 degreesN, between 35% and 55% of the seasonal ozone decline during the summer occurs at altitude s below 100 hPa. The overall uncertainties, associated primarily with calcu lations of the residual circulation and eddy transport, are relatively larg e, and thus prevent accurate and useful constraints on the ozone chemical r ate in the lower stratosphere.